WASTE HEAT ENERGY SUPERCRITICAL CARBON DIOXIDE RECOVERY CYCLE ANALYSIS AND DESIGN

The US Department of Energy has estimated that 280,000 MW of recyclable waste heat is expelled annually by U.S. industries. Further estimates suggest that harvesting it could result in a savings of $70 billion to $150 billion per year (1). Thus, any efficiency increase will result in savings to energy producers. Supercritical carbon dioxide (SCO2) provides unique advantages over alternative waste heat recovery systems however, it also produces unique design challenges. We propose a novel energy recovery device based on a SCO2 regenerative Rankine cycle for small-scale (1kW to 5kW) heat recovery. This study presents a thermodynamic SCO2 cycle analysis for waste heat recovery from low temperature (200°C 500°C) sources using small mass flow rates (20 – 60 grams/sec). This paper will present a prototype SCO2 cycle architecture including details of key system components. Preliminary modeling suggests that SCO2 systems are viable for low temperature waste heat recovery.